The 27 crewmen of the fishing vessel Daichi Shoei Maru were forced to abandon ship after the vessel caught fire while 500 miles east of Guam.   The vessel reported to the Japan Coast Guard that the vessel was on fire and required assistance.   The Coast Guard contacted a nearby 17,800 dwt boxship South Islander to aid in the rescue of the fishermen.  A Coast Guard aircraft was also deployed and was able to direct the rescue effort.    Before the South Islander reached the Daichi Shoei Maru, the crew abandoned ship and went to the life rafts.   Moments later, the fishing vessel exploded leaving the Daichi Shoei Maru a burning wreck.   Luckily, the South Islander reached the seen shortly afterwards and all 27 crewmen were safely transfered to the freighter.   No reports to the cause of the fire.